Reading only once

[bPHP]

How can I read from a certain table only once after it's changed? I'm constantly reading from a table because I need to display it, but I'm not sure how to avoid reading from it when it hasn't been updated (it can be updated from many sources).

 

Any suggestions?

 

Thanks!

[bPHP]

No ideas?

[fenway]

Caching?

[bPHP]

How? I still need to check if the table was updated? I'm kind of noobish with this

[ignace]

From which sources is this table updated? And how? If all these different sources use your API just different components then you can abstract a method that will invalidate/update the cache file something like:

 

abstract class MySource {
    final public function store($data) {
        $this->_store($data);
        $this->_update();
    }

    private function _update() { /* invalidate/update cache */ }
    
    abstract protected function _store($data);
}

[bPHP]

This table keeps some kind of interaction between users... Like a chat between users. When one of the users types something and then sends it, this is saved to the database, inside the interaction table of those two users. Right now I think my design is pretty bad; I am using Ajax to constantly call a php function that reads from the interaction table, gets the last message and displays it. I don't really know how to avoid having to constantly refresh or how to know when to go to the database for new changes (like a message sent from the other user). Is my problem clear? Please tell me if I haven't explained it well enough... Thanks again!

[fenway]

Seriously, read about caching.

[ignace]

I suddenly come to think about something how about the following setup:

 

1. Client: An IFrame that loads the XML file and applies an XSLT template

2. A stored XML file only known to A and B

 

Now everytime a user submits it modifies the XML file (append node). Both clients refresh the IFrame at regular intervals. I wonder what other downsides this could have besides privacy/security? Would there be any gain performance wise? Because this would be the equivalent of multiple databases instead of many people searching (query) through one database each session would have it's own "database"